U.S. patent number 5,193,240 [Application Number 07/822,997] was granted by the patent office on 1993-03-16 for mould and method for producing shoe soles of injected plastics material, comprising an empty chamber visible through a transparent material.
This patent grant is currently assigned to Protec s.r.l.. Invention is credited to Francesco Salpietro.
United States Patent |
5,193,240 |
Salpietro |
March 16, 1993 |
Mould and method for producing shoe soles of injected plastics
material, comprising an empty chamber visible through a transparent
material
Abstract
Process for producing shoe soles of injected plastics material,
which soles have an empty chamber visible through a transparent
material, which process comprises the following steps: a)
injection, into a hollow region comprised between a mobile die and
a first removable plate, of a multipart tread sole, with at least
one of said sole parts being made from a transparent material; b)
injection, into a region comprised between said first removable
matrix and a second, removable matrix, of a shaped body comprising
a perimetrical wall 13 and a top wall 14; c) removal of said first
matrix and injection, into the hollow region comprised between said
tread sole and said shaped body, of a layer 17 made of a material
suitable for bonding the shoe sole and said shaped body to each
other; d) removal of said second matrix and injection, into the
hollow region comprised between the vamp, the tread sole and the
external side of said shaped body, of a material which constitutes
the intersole; e) possible either partial or total filling of the
empty chamber comprised between the tread sole and said shaped
body, with a coloured liquid material.
Inventors: |
Salpietro; Francesco (Padova,
IT) |
Assignee: |
Protec s.r.l. (Padova,
IT)
|
Family
ID: |
11360545 |
Appl.
No.: |
07/822,997 |
Filed: |
January 21, 1992 |
Foreign Application Priority Data
|
|
|
|
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Aug 6, 1991 [IT] |
|
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MI91A 002214 |
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Current U.S.
Class: |
12/146B;
12/142RS; 12/142T; 264/244; 425/119 |
Current CPC
Class: |
A43B
1/0072 (20130101); B29D 35/082 (20130101) |
Current International
Class: |
B29D
31/51 (20060101); B29D 31/50 (20060101); A43D
065/00 (); A43D 065/02 () |
Field of
Search: |
;12/146B,142RS,142T
;264/244,254,255 ;425/119 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sewell; Paul T.
Assistant Examiner: Patterson; M. D.
Attorney, Agent or Firm: Notaro & Michalos
Claims
I claim:
1. Process for producing shoe soles of injected plastics material,
which soles have an empty chamber visible through a transparent
material, which process comprises the following steps:
a) injection, into a region comprised between a mobile die and a
first, removable plate, of a multipart tread sole, with at least
one of said sole parts being made from a transparent material;
b) injection, into a region comprised between said first removable
plate and a second, removable plate, of a shaped body comprising a
perimetrical wall 13 and a top wall 14;
c) removal of said first plate and injection into the region
comprised between said tread sole and said shaped body, of a layer
17 made from a material suitable for bonding the shoe sole and said
shaped body to each other;
d) removal of said second plate and injection, into the region
comprised between the vamp, the tread sole and the external side of
said shaped body, of a material which constitutes the
intersole;
e) either partial or total filling of the empty chamber comprised
between the tread sole and said shaped body, with a coloured liquid
material.
2. Process according to claim 1, characterized in that the
injections of (a) and (b) steps are carried out simultaneously.
3. Mould for producing shoe soles of injected plastics material
comprising a hollow chamber visible through a transparent material,
characterized in that said mould comprises:
a last 1 destined to receive the shoe vamp, which is fitted on
it;
a die 3 with the pattern of the tread sole, installed on a mobile
support suitable for causing said die to be urged against said last
1;
a first plate suitable for defining, in the region comprised
between it and said die, a space for the injection of the tread
sole, with said first plate being provided on its lower side, with
a relieved rim 11 with closed contour;
a second intermediate plate 5 suitable for being brought to rest
against said first plate 6, with said plates 5 and 6 being so
shaped as to define, between them, a shaped body 12 with a
downwards protruding edge, said edge corresponding, as for shape
and size, with the relieved element 11 in the lower face of the
plate 6;
means suitable for placing said plates between said last and said
die, and for removing them from that position.
Description
The present invention proposes a mould and a method for producing
shoe soles of injected plastics material, which shoe soles comprise
an empty chamber visible through a transparent material.
In particular, by the method according to the present invention, a
shoe sole of four or more colours can be produced, in which a
portion of the tread layer is made from a transparent material, and
which contains an inner empty chamber, visible from the outside
through a transparent portion of said tread sole.
Such an empty chamber can be filled with a material, such as a
coloured liquid, in order to attain novel aesthetical effects.
Apparatuses for manufacturing soles of two or more colours are
known, which apparatuses comprise a last on which the vamp is
placed; a mould, or movable die with the contour of the tread, a
pair of sealing rings to laterally close the mould and one or more
intermediate plates, so contoured as to make it possible
intermediate sole layers to be produced, still by injection.
These machines are used in order to produce shoe soles which are
constituted by two or three layers of materials of different
colours, or having different characteristics. For example, the
tread may be made from a material endowed with a high mechanical
strength, and the intersole may be made from a flexible, soft
material.
Oftentimes, these moulds are installed on a carrousel which, by
revolving, causes them to sequentially reach several injectors
which inject the molten material into the mould.
Also machines are known, in which at least two sole layers can be
injected simultaneously, e.g., the one of said layers into the
upper side, and the other layer in correspondance of the lower
portion of an intermediate plate inserted between the last and the
die.
When this injection is complete, the plate is removed, the die is
approached to the vamp, and an intersole layer is injected which
bonds both previous layers to each other.
The market, in particular in apparel sector, is always looking for
novel solutions, and within this context the present invention
proposes now a mould and a method for producing four-colour shoe
soles having a transparent portion in their tread, which allows an
empty chamber provided in correspondence of this portion, to be
seen into.
Said empty chamber can be partially filled, e.g., with a coloured
filling liquid, with novel, unforeseeable aesthetical effects.
These, and still other purposes, are achieved by means of an
apparatus according to the characterizing portion of the appended
claims.
The present invention is disclosed now in detail, for merely
exemplifying, non-limitative purposes, with reference to the
accompanying drawing, in which:
FIG. 1 shows a sectional view of a mould according to the
invention, during the first step of shoe sole injection;
FIG. 2 shows a sectional view of the same mould, during the
intermediate manufacturing step;
FIG. 3 shows the sectional view of the mould during the shoe sole
completion step.
The mould according to the invention comprises a last 1 on which a
vamp 2 is fitted, and a bottom die 3, installed in a known way on
such devices as, e.g., a hydraulic piston, which drive said bottom
die to move in vertical direction in order to approach it towards,
and move it away from, the last 1.
At its sides, the mould is closed by a pair of contoured half-rings
4, and two intermediate, removable plates 5 and 6 are provided.
These removable plates are installed on supports capable of
inserting them between the last 1 and the die 3, and of removing
them too.
The devices which drive the movements of the plates are already
known and, due to this reason, they are not discussed herein in
detail.
The process according to the invention is disclosed now, and the
innovative features of the mould are illustrated during the course
of the disclosure.
During the first step the plates 5 and 6, overlapped to each other,
are placed between the last 1 and the die 3.
The die 3 is then brought into contact with the bottom plate, and
the region around the vamp is closed by means of the rings 4.
In the die 3 the pattern is provided of the tread which is
subdivided into three distinct regions, 8, 9 and 10, by a pair of
partitioning walls 7 and 8. Said three regions 8, 9, 10 of the
tread are fed with injection materials by three respective
injection channels, indicated with the reference numerals 8', 9',
10'.
On its lower side, the plate 6 is provided with a relieved rim 11,
e.g., with a closed polygonal or curvilinear outline, the function
of which will become clearer later on, during the course of the
disclosure.
With the mould being in this position, three injections are carried
out either sequentially or simultaneously, into the regions 8, 9
and 10, using, e.g., different-coloured materials; in particular,
in region 9 an injection with a transparent material is carried
out.
An injection is carried out simultaneously into the region
comprised between the plates 5 and 6, which are so shaped as to
define a shaped body indicated with the reference numeral 12, which
has a closed side wall 13 and a top wall 14.
The wall 13 is provided, at its bottom, with an edge with shape and
dimensions corresponding to those of the relieved rim provided on
the lower side of plate 6.
In its top portion, the wall 13 is so shaped as to define two edges
15 protruding upwards, slightly spaced apart from each other.
When the first injection step is complete, the mould is opened, the
bottom plate 6 is removed, the mould is closed again, and the die 3
is moved upwards, with the tread sole being brought into contact
with the upper plate 5.
Consequently, the lower edge of the wall 13 enters the groove which
the relieved rim 11 generated in the transparent portion 9 of the
shoe sole.
In that way, between the sole portion 9 and the shaped body 12, an
empty chamber is defined, which is indicated with the reference
numeral 15 in FIG. 2.
The length of the lower edge of the wall 13 is longer than the
depth of the groove generated by the relieved rim 11 in the region
9 of shoe sole, so that, when the die 3 is brought into contact
with the plate 5, a thin gap remains empty between the shaped body
12 and the tread sole.
This thin gap is filled during the second injection step (FIG. 2),
with the material 17, which anchors the tread sole and the shaped
body 12 to each other.
The mould is opened once more, the plate 5 is removed, and the die
3, to which the tread sole and the shaped body 12 remained
adherent, is brought to rest against the upper last 1 and the vamp
2.
This situation is illustrated in FIG. 3.
During the latter step, the material 18 destined to constitute the
intersole, and which will definitely anchor the tread sole to the
vamp, is injected.
The edge 15, protruding upwards from the shaped body 12 is pressed
against the vamp, thus preventing the intersole material from
penetrating between the last 12 and the vamp, with the risk of said
material penetrating, or even completely filling, the underlying
empty space, being thereby prevented.
The footwear is thus complete, and the empty chamber 15 can be now
partially filled, e.g., with a coloured liquid, which will remain
visible through the transparent portion 9 of the sole tread.
The liquid can now be filled into the hollow chamber 15 in a known
way, e.g., it can be injected by means of an injection needle.
In that way, a footwear with a shoe sole of four or more colours
can be obtained, which contains a hollow chamber closed by a
transparent wall, and partially filled with a coloured material,
the movement of which can be seen through the tread sole.
In particular, also the shaped body 12 can be made from a
transparent material, thus enabling the colour to be seen also
through the side wall of the shoe sole.
Many modifications and alternative forms of practical embodiment
will be clear to those skilled in the art, all of which shall have
to be understood as falling within the purview of the present
invention.
* * * * *